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This article in JEQ

  1. Vol. 37 No. 4, p. 1567-1574
     
    Received: June 25, 2007


    * Corresponding author(s): hae1@psu.edu
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doi:10.2134/jeq2007.0338

Managing Biosolids Runoff Phosphorus Using Buffer Strips Enhanced with Drinking Water Treatment Residuals

  1. D. J. Wagner,
  2. H. A. Elliott *,
  3. R. C. Brandt and
  4. D. Jaiswal
  1. Agricultural and Biological Engineering Dep., Pennsylvania State Univ., University Park, PA 16802

Abstract

Vegetated buffers strips typically have limited ability to reduce delivery of dissolved phosphorus (DP) from agricultural fields to surface waters. A field study was conducted to evaluate the ability of buffer strips enhanced with drinking water treatment residuals (WTRs) to control runoff P losses from surface-applied biosolids characterized by high water-extractable P (4 g kg 1). Simulated rainfall (62.4 mm h−1) was applied to grassed plots (3 m × 10.7 m including a 2.67 m downslope buffer) surface-amended with biosolids at 102 kg P ha−1 until 30 min of runoff was collected. With buffer strips top-dressed with WTR (20 Mg ha−1), runoff total P (TP = 2.5 mg L−1) and total DP (TDP = 1.9 mg L−1) were not statistically lower (α = 0.05) compared to plots with unamended grass buffers (TP = 2.7 mg L−1; TDP = 2.6 mg L−1). Although the applied WTR had excess capacity (Langmuir P maxima of 25 g P kg−1) to sorb all runoff P, kinetic experiments suggest that sheet flow travel time across the buffers (∼30 s) was insufficient for significant P reduction. Effective interception of dissolved P in runoff water by WTR-enhanced buffer strips requires rapid P sorption kinetics and hydrologic flow behavior ensuring sufficient runoff residence time and WTR contact in the buffer. Substantial phosphate-adsorbent contact opportunity may be more easily achieved by incorporating WTRs into P-enriched soils or blending WTRs with applied P sources.

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Copyright © 2008. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyAmerican Society of Agronomy, Crop Science Society of America, and Soil Science Society of America